Electrolytic cells



Dec. 11, 1956 R. Q. BOYER ErAL ELECTROLYTIC CELLS Original Filed Sept. 14, 1944 5 Sheets-Sheet 1 Dec. 11, 1956 R. Q. BOYER ETAL 2,773,824

ELECTROLYTIC CELLS Original Filed Sept. 14, 1944 5 Sheets-Sheet 2 /Q .39 38a 36- 56a 3.9

ROBERT C2. BOYER `SCOTT 5. K/LNER A TTORNE Y DeC- 11, 1956 R. Q. BOYER ETAL 2,773,824

ELECTROLYTIC CELLS Original Filed Sept. 14, 1944 5 Sheets-Sheet 3 ATTORNEY Dec 11, 1956 R. Q. BOYER ETAL 2,773,824

ELECTROLYTIC CELLS Original Filed' Sept. 14, 1944 5 Sheets-Sheet 4 ATTORNEY 5 Sheets-Sheet 5 Original Filed Sept. 14, 1944 nLEcrnoLYrrc CELLS Robert Q. Boyer, Berkeley, Calif., and Scott B. Kilmer, Knoxville, Tenn., assignors to the United States of America as represented by the United States Atomic Energy Commission Original application September 14, 1944, Serial No. 554,044. Divided and this application June 7, 1945, Serial No. 598,012

6 Claims. (Cl. 204-212) The present invention relates to electrolytic cells and the present application is a division of our copending application, Serial No. 554,044, iiled September 14, 1944.

2,773,824 Patented Dec. 11, 1956 perimeter of the bottom wall 13 being received in interior grooves formed in the side walls 14 and in the end walls 'adjacent the lower edges thereof. Further, the lower casing section 11 includes a rectangular outwardly extending ange 16 disposed about the upper open end thereof and rigidly secured to the adjacent outer surfaces of the side walls 14 and the end walls 15. Similarly, the upper casing section 12 is substantially rectangular in plan, including a at bottom wall 17, upstanding side walls 18 and upstanding end walls 19, secured together in liquid-tight relation, the lower edges of the side walls 18 and the end walls 19 being received in a rectangular groove formed in the upper surface of the bottom wall 17, and disposed inwardly from the perimeter thereof. Accordingly, the bottom wall 17 of the upper casing section 12 extends outwardly from the side walls 18 and the end walls 19 in order to define in effect a rectangular outwardly extending ange 20, dis- An object of the invention is to provide an improved l electrolytic cell that is especially designed for use in the salvage of uranium from a relatively large volume of solution.

Another object of the invention is to provide an electrolytic cell of improved construction and arrangement that is compact and ecient in operation.

Another object of the invention is to provide an electrolytic cell comprising an improved arrangement for circulating two solutions that arerto be subjected to electrolysis through the respective anode and cathode compartments thereof.

Another object of the invention is to provide an electrolytic cell comprising an improved arrangement for introducing gas into the contained electrolyte.

The invention, both as to its organization and method of operation together with further objects and advantages thereof, will best be understood by reference to the following specication taken in connection with the accompanying drawings, in which Figure l is a fragmentary plan view of an electrolytic cell embodying the present invention, and in conjunction with which there may be carried out the process of the present invention; Fig. 2 is a fragmentary longitudinal sectional view of the electrolytic cell taken along the line 2 2 in Fig. 1 with certain structure shown in elevation for clarity; Fig. 3 is a transverse sectional view of the electrolytic cell taken along the line 3 3 in Fig. 2; Fig. 4 is a transverse sectional view of the electrolytic cell taken along the line 4 4 in Fig. 2; Fig. 5 is a transverse sectional view of the electrolytic cell taken along the line 5 5 in Fig. 2;

Fig. 6 is an enlarged fragmentary sectional View of one of the anode compartments in the electrolytic cell, taken along the line 6 6 in Fig. 5; Fig. 7 is an enlarged fragmentary sectional view of the lower portion of the lefthand side wall of the upper casing section of the electrolytic cell, taken along the line 7 7 in Fig. 6, and illustrating the arrangement of the gas conduit embedded therein; Fig. 8 is a reduced side elevational view, partly in section, of the housing of the electrolytic cell; and Fig. 9 is a diagrammatic illustration of a solution treatment system in which the electrolytic cell is incorporated.

Referring now more particularly to Figs. l to 7, inclusive, of the drawings, there is illustrated an electrolytic cell 10 that embodies the features of the present invention and comprises a lower casing section 11 and an upposed about the lower closed end of the upper casing section 12. Preferably, the parts of the lower casing section 11 and the upper casing section 12 are formed of laminated insulating material, the precise nature of which forms no essential part of our invention.

The upper casing section 12 is assembled upon the lower casing section 11, the rectangular anges 20 and 16 being congruent. Also, a sealing gasket 21, formed of rubber or the like, is arranged between the lower surface of the bottom wall 17 and the upper edge of the Side walls 14 and the end walls 15, and extending between the anges 20 and 16. Finally, the flanges 16 and 20 are removably secured together in liquid-tight relation by a series of bolts 22, extending through aligned openings formed therein, the ends of the bolts 22 receiving nuts 23. Suitable washers surround the Shanks of the bolts 22 'and are respectively disposed between the heads of the bolts 22 and the upper surface of the liange 20, and between the nuts 23 and the lower surface of the iiange 16. Further, a drain pipe 26 is threaded in an opening formed in the bottom wall 13 adjacent the left-hand end wall 15, which drain pipe communicates with the interior of the lower casing section 11. The end of the drain pipe 26 terminates in a petcock 27, whereby the drain pipe 26 may be selectively opened or closed.

A number of laterally extending longitudinally spacedapart slots 17a are provided through the bottom wall 17 within the area bounded by the side walls 18 and the end walls 19; and a corresponding plurality of upstanding laterally extending and longitudinally spacedapart pairs of partition elements 28 are carried by the upper surface of the bottom wall 17, the individual partition elements 23 of each pair being disposed on the opposite sides of a slot 17a. More particularly, eachupstanding partition element 28 is retained in place by a pair of aligned upstanding slots 18a, formed in the inner surfaces of the side walls 18 as best shown ifi-Fig. 5, and an aligned laterally extending recess 17b, formed in the upper surface of the bottom wall 17 adjacent a slot 17a. Similarly, an upstanding laterally extending partition element 29 is carried by the upper surface 'of the bottom wall 17, the partition element 29 being spaced longitudinally and to the right-hand side of the partition element 28 disposed most remote from the left-hand end wall 19. Also, the upstanding partition element 29 is retained in place in a manner identical to that previously explained in conjunction with' each partition element 28. As will later become apparent, partition element 29 forms the barrier between the righthandmost anode compartment, as viewed in Fig. 2, and the open space 65 within the casing, which space provides a cathode compartment.

The various partition elements 28 and the partition element 29 comprise rectangular plates formed of a porous semipermeable insulating material of the ceramic type, such as Alundum or sintered Pyrex glass. Collectively, the pairs of partition elements 2S and the partition element 29 constitute partition structure dening a plurality of interposed anode and cathode compartments 30 and 31, respectively, which are separately contained in the upper casing section 12. More particularly, the two partition elements 28 of each pair cooperate ,with each other and with the portions of the side walls 1S disposed therebetween to define a cathode compartment 31 having an open lower end formed by a cooperating slot 17a. Similarly, each left-hand partition element 28 of a pair cooperates with the right-hand partitionel'ement 28 of an adjacent pair and with the portions of the side walls 18 and the bottom wall 17 disposed therebetween to dene an anode compartment 30 having a closed lower end. Further, the left-hand partition element .28 of the pair disposed adjacent 'the left-handend wall 19 cooperates therewith'and with thepor'tionsuof the side walls 18 and .'the bottomV wall 1 7 disposed therebetween to deine the anode .compartmenthi-Gddisposed immediately adjacent the left-hand end wall Finally, the right-hand partition element 28 of the pair disposed adjacent the partition element l29 cooperates therewith and with the portions Vof 'the side walls 18 and the bottom wall h17 disposed therebetween to dene the anode compartment 3 disposed most Vremote from the left-handendwall19..

The yupper vedges of the various pairs of partitionelements.'28 and the partition element 29 are disposed substantially iiush with the upper edges of the side walls 18, and the upper edges of the side walls 18 are substantially flush with the upper edges of the end Walls `19; wherebythe upper edge of the upper casing section 12 is substantially flat and parallel to the bottom wall 13 of the lower casing section 11. Further, a pair of conductors in the form of busbars 32 formed of copper or the like, are secured to the upper edges of theside walls 18 by a number of screws 33. The left-hand ends of lt he busb2 irs 32 are secured together by a conducting st rap 34VA by screws 35; and a conducting terminal 36 is secured to the mid-portion of the strap 34 by a screw 37. A plurality of anode elements 38 is carried by the busbars 32 and arranged in the respective anode cornpartments 30. Each of the anode elements 38 com prises a substantially rectangular plate provided at its upper end with laterally and oppositely extending lugs 38a which overhang the respective busbars 32. The anode elements 38 are formed of a conducting material resistant to c hlorinev and hydrochloric acid solutions, such as graphite or platinum or a platinum-iridium alloy, and are electrically connected to the busbars 32 by terminal structure including screws 39 and exible conductors 40. More particularly, the flexible conductors 40 are of the braid or pigtailptype, one end of each pigtail 40 being brazed or soldered to the adjacent busbar 32, and the other Iend of the pigtail '40 being provided with Van `eyelet through vwhich the associated screw 39 extends, the screw 39 extending through the adjacent lug 38a formed on the cooperating anode element 38.y Thus, the terminal36 is connected by low resistance paths to each of the anode -elements 38 in multiple, whereby collectively the anode elements 38 constitute an anode. A longitudinally extending shaft 41 is rotatably mounted in two bearing brackets 42 and 43, secured to the lower surface of the bottom wall 1'7 by screws 44 and 45, respectively. rl'he bearing brackets 42 and 43 are alignedv substantially along the longitudinal centerline of the bottom wall 17 and consequently of the electrolytic cell 10, the bearing bracket 42 being disposed adjacent the left-hand end wall 1S, and the bearing bracket 43 being disposed remote from the left-hand end wall and spaced some distance from the right-hand endwalll. The bearing brackets 42 and 43 may suitably comprise complementary sections formed of stainless steel and secured together and to the bottom wall 17 by the screws 44 and 4S, as previously noted. The shaft 41 carries a plurality of longitudinally spaced apart cathode members 46 in the form of disks. Each of the cathode members 46 is rigidly secured to the shaft 41, so that it is rotatable therewith, and extends downwardly into the lower casing section 11 and upwardly through a cooperating one of the slots 17a into a cooperating one of the cathode compartments 31 formed in the partition structure within the upper casing section 12. The cathode members 46 are formed of a conducting material resistant to chlorine and hydrochloric acid solutions that readily amalgamates with mercury, such, for example, as nickel. The cathode members 46 are electrically connected to the shaft 41 in multiple and collectively constitute a cathode.

A laterally extending opening 17e, as best shown in Fig. 1, is provided through the bottom wall 17 adjacent the right-hand end wall 19; and a bevel gear 47 is rigidly secured to the right-hand end of the shaft 41, whereby the upper portion of the bevel gear 47 extends upwardly through the opening 17C into the upper casing section 12, and the lower portion of the bevel gear 47 extends downwardly into the lower casing section 11. More particularly, the bevel gear 47 is provided with a collar '48 which is secured to the right-hand end of the shaft 41 by a setscrew 49 and carries a flange 50 engaging -the right-hand side of the bearing bracket 43 to provide ya thrust bearing for the shaft 41.

The bevel gear 47 meshes with a bevel gear 51 rigidly secured to an upstanding operating shaft 52 adjacent -the lower end thereof. The extreme lower end of the operatingshaft 52 is supported in a thrust bearing 53`carried by a bearing bracket 54; Vand the upper end of the operating shaft 52 is supported by a guide bearing '55 carried by a bearing strap 56. More particularly, the bearing bracket 54 comprises Ytwo laterally upwardly and Voutwardly extending legs 57, which are secured by screws -58 to the lower surface of the bottom wall '17, and allongitudinallyupwardly and outwardly extending leg 59, which is `secured by the screw 45 to the bearing bracket 43. The thrust bearing 53 comprises a threaded step f60ac commodating adjustment of the operating shaft 52 in the vertical direction, and consequently proper kmesh between the bevel gear 51 carried thereby and the bevel gear 47 carried by the shaft 41. The bearing strap 56 xtendslaterally across the upper casing section 11, 4and the opposite ends thereof are suitably anchored =to the upper edges ofthe side walls 18 by screws`61.

A pool of mercury 62 is arranged in the lower casing section 11, the volume of the mercury 'constituting the l pool beingsuch that columns of mercury rise inthe slots 17a'into the cathode compartments 31. Preferably, the columns of mercury rise into the cathode compartments 31 a slightV distance above the upper surface of the'bottom wall 17,` whereby the shaft 41`and the lower segnlents of the cathode members 46 are immersed in the mercury pool 62. An upstanding cathodeplate 63,'asrbestv shown in Fig. 2, extends through the upper casing section 12 downwardly'through the opening 17C and terminates in the lower casingsection 11, whereby the-lower .end of the cathodeplate 63 is immersed in the mercury pool 62. A substantially U'shaped clip 64 is rigidly securedto the cathode plate 63'and is adapted lto overhang the adjacent upper edge of the right-hand end .wall- 19,thereby securely to retain the cathode. `plate63 imposition.

Further, a body of'electrolyte 65.is arrangedinsthe upper casing V'section 12 as a-head` upon the.mercury pool 62, the body of electrolyte 65 filling Athe various anode and cathode compartments 30 and'31, respectively, and electrically communicating through the porous. partition structure including the partition elements'.28and 29, the'mass of the body of electrolyte 65lbeing such that the upper segments of thel cathodemembers 46 far e completely immersed therein. Aswill later be described in detail, the anode compartments 30 in the upper casing section 12 are arranged in groups, each group containing several adjacent individual anode compartments, the individual anode compartments in each group being connected in series relation, and the different groups of anode compartments being connected in parallel relation by a first conduit system. Similarly, the cathode compartments 31 in the upper casing section 12 are arranged in groups, each group containing several adjacent individual cathode compartments, the individual cathode compartments in each group being connected in series relation, and the different groups of cathode compartments being connected in parallel relation by a second conduit system.

Considering now the illustrated embodiment of the electrolytic cell in greater detail, the partition structure comprises nine pairs of partition elements 28, whereby nine individual cathode compartments 31 are formed in the upper casing section 12 and arranged in longitudinally spaced apart relation, each of the cathode compartments 31 communicating through the associated slot 17a with the lower casing section 11. Also, the rotatably mounted shaft 41 carries nine longitudinally spaced apart cathode members 46 which extend through the respective slots 17a into the respective cathode compartments 31. Further, the partition structure comprising the nine pairs of partition elements 28 and the partition element 29 forms ten individual anode compartments 30 in the upper casing section 12, arranged in longitudinally spaced apart relation and in interposed relation with respect to the cathode compartments 31. Thus, in the partition structure an anode compartment 30 is positioned on either side of each cathode compartment 31. The ten anode compartments 30 are arranged in three groups, two end groups of three individual anode compartments each and a middle group of four individual anode compartments. The three groups of anode compartments 30 are connected in parallel, and the individual anode compartments 30 in each group are connected in series relation by the first conduit system mentioned. Similarly, the nine cathode compartments 31 are arranged in three groups of three individual cathode compartments each. The three groups of cathode compartments 31 are connected in parallel and the individual cathode compartments 31 in each group are connected in series relation by the second conduit system mentioned.

Referring now more particularly to Figs. 1, 2 and 9, the iirst conduit system mentioned comprises three inlet pipes 101, respectively serving the three groups of anode :compartments 30 and respectively communicating with the first, fourth and eighth individual anode compartments 30 positioned fromrthe right-hand side of the elecftrolytic cell 10 toward the left-hand side thereof, as viewed in the figures mentioned. Also, the rst conduit :system mentioned comprises three outlet pipes 102, re- :spectively serving the three groups of anode compartments 30 and respectively communicating with the third, :seventh and tenth individual anode compartments 30. 'The adjacent ends of the individual anode compartments 'in each group are connected in series relation between ithe associated inlet pipe 101 and the associated outlet jpipe 102 by U-shaped header pipes 103. In conjunction with the rst conduit system, it is noted that a series of :aligned openings 1817 are formed in the side walls 18 and fcommunicate with the anode compartments 30 in order to receive the various pipes 101, 102 and 103, the openings 18b being disposed well above the lower ends of the fanode elements 38 so that the lower portions of the anode telements are completely immersed in the body of elec- :trolyte 65.

Accordingly, it will be understood that a iirst stream fof electrolyte may be conducted from a rst of the inlet pipes 101 through a first group of three individual anode compartments 30 in series relation to a irst of the outlet 4pipes 102. Similarly, a second stream of electrolyte array be conducted from a second of the inlet pipes 101 .through the Segond group f four individual vanode coni; Partments 30 in series relation to a second of the outlet:

pipes 102. Finally, a third stream of electrolyte may be conducted from a third of the inlet pipes 101 through the third group of three individual anode compartments 30 in series relation to a third of the outlet pipes 102. Accordingly, the rst conduit system connects the individual anode compartments 30 in the electrolytic cell 10 in parallel series relation.

The second conduit system mentioned comprises three inlet pipes 104 respectively serving the three groups of cathode compartments 31 and respectively communicating with the first, fourth and seventh individual cathode compartments 31 positioned from the right-hand side of, the electrolytic cell 10 toward the left-hand side thereof,

as viewed in the figures mentioned. Also, the second conduit system mentioned comprises three outlet pipes 105 respectively serving the three groups of cathode compartments 31 and respectively communicating with the third, sixth and ninth individual cathode compartments 31. The adjacent ends of the individual cathode compartments in each group are connected in series relation between the associated inlet pipe 104 and the associated outlet pipe 105 by U-shaped header pipes 106. In conjunction with the second conduit system, it is noted that a series of aligned openings 18x.` are formed in the side walls 18 and communicate with the cathode compartments 31 in order to receive the various pipes 104, 105 and 106, the openings 18e being disposed above the cathode members 46 so that the upper segments of the cathode members are completely immersed in the body of electrolyte 65.

Accordingly, it will be understood that a first stream of electrolyte may be conducted from a first of the inlet pipes 104 through a first group of three individual cathode compartments 31 in series relation to a irst of the out let pipes 105. Similarly, a second stream of electrolyte may be conducted from a second of the inlet pipes 104 through the second group of three individual cathode compartments 31 in series relation to a second of the outlet pipes 105. Finally, a third stream of electrolyte may be conducted from a third of the inlet pipes 104 through the third group of three individual cathode compartments 31 in series relation to a third of the outlet pipes 105. Accordingly, the second conduit system connects the individual cathode compartments 31 in the electrolytic cell 10 in parallel series relation.

Again referring to Figs. l to 7, inclusive, it is noted that two longitudinally extending pipes and 111 are respectively embedded in the two side walls 18 of the upper casing section 12, the pipes 110 and 111 being respectively embedded in the left-hand and right-hand side walls 18, as viewed in Figs. 5 and 6. More particularly, the pipe 110 is arranged in a longitudinally extending opening formed in the left-hand side wall 18 adjacent the lower edge thereof and cemented in place in a fluid-tight manner by a layer of a suitable cement 112; and the pipe 111 is arranged in a longitudinally extending opening formed in the right-hand side wall 18 adjacent the lower edge thereof and cemented in place in a fluid-tight manner by a layer of a suitable cement 113. The cement employed in the layers 112 and 113 may be of any suitable type, the precise nature of which forms no essential part of our invention.

A series of longitudinally spaced apart openings 110a are formed in the pipe 110 and communicate through connecting and registering downwardly extending holes 114 provided in the layer of cement 112 and in the lefthand side wall 18, the holes 114 communicating with the various anode compartments 30. More particularly, each hole 114 formed in the left-hand side wall 18 communicates with the associated anode compartment 30 adjacent the lower left-hand corner thereof and on the front side of the anode element 38 arranged in the anode compartment 30, as viewed in Fig. 6. Similarly, a series of longitudinally spacedv apart openings .11111 are formed in the pipe 1/11 and communicate through connecting and registering downwardly extending holes 115 provided in the layer of cement 113 and in the right-hand side wall 18, the holes 1.15 communicating with the various anode compartments 30. More particularly, each hole 115 formed in the right-hand side wall 18 communicates with the associated anode compartment 30 adjacent the lower right-hand corner thereof and on the back side of the anode element 38 arranged in the anode compartment 30, as viewed in Fig. 6. Accordingly, the pipe 110 communicates through the openings 110a with the lower left-hand corners of the various anode compartments 30 on the front sides of the anode elements 38; while the pipe 111 communicates through the openings 111a with the lower right-hand corners of the various anode compartments 30 on the back sides of the anode elements 38.

The pipes 110 `andl-ll form fa part of Va third conduit system containing gas under pressure, whereby the Ygas may be forced through the pipes 1'10 and 111 and the respectively communicating holes k114 and 115 into the various anode compartments 30 on either side -of the anode elements 38. Also, inlet and outlet conduits 116 land 117 are supported in openings formed in the end walls of the lower casing sectionll and form apart of a fourth conduit system, whereby mercury may be circulated through the mercury pool 62 contained in the lower casing sectionll.

Referring now to "Fig, 8, the electrolytic cell 10 is arranged in a substantially huid-tight housing '120 cornprising lower and upper housing sections 121 and 122, respectively, provided with outwardly directed anges 123 and 124 secured together by a series of bolts 125' extending through aligned openings formed therein, a suitable sealing gasket 126, formed of rubber or the like, being arranged between the anges 123 and 124. The wall of the lower housing section 121 supports two insulating bushings 127 and 128, arranged in gastight relation `therewith, through which conductors are adapted to extend, whereby thetpositive and negative terminals of a suitable source of supply may be respectively connected to the terminal 36 and the plate 63, shown inFigs. 1 and 2, in an appropriate manner. Also, the wall of the lower housing section 121 supports two conduits A129 and 130, arranged in gastight relation therewith, which are appropriately connected to the pipes'101 and 102 and form a part of the lirst conduit systemrpreviously mentioned, whereby an electrolyte may be circulated through the anode compartments 30 in parallel series relation in the manner previously explained. Similarly, the wall of the lower housing section 121 supports two conduits 131 and 1'32,arranged in gastight relation therewith, which are appropriately connected to the pipes 104 and 105 and form a part of the second conduit systempreviously mentioned, whereby an electrolyte may be circulated through the cathodecompartmentsl inparallel series relation in the manner previously explained.

Further, the wall of the lower housing section 121 supports a conduit 133, arranged in gastight relation therewith, which is appropriately connected to the pipes "110`and 111 and forms apart of the third conduit system previously mentioned, whereby gas under pressure may beconducted into the anode compartments 30 in the 'manner previously explained. The wall of the upper housing section 1.22 supports a conduit 134, arranged in 'gastight relation therewith, and communicating with the interior of the housing 120, wherebygas liberated from the electrolytic cell 10-and accumulated within the housing 120 may be'conducted to'the exterior in a manner more `fully explained hereinafter. Finally, the wall of the lower housing section-121 supports twofconduitsl35and v1536, farrangecl in; gastight relationV therewith; which are appropriately connected to the pipes 116 and 117 and form 8 a part of the fourth conduit system previously mehr. tioned, whereby mercury may be circulated through the pool of mercury 62 arranged in the lower casing section 11 of the electrolytic cell 10 in the manner previouslyexplained.

The operating shaft 52 extending into the electrolytic cell 10 is suitably connected to an electric motor 13,7 supported by a bracket 138 carried by the wall of the` lower housing section `121; and the wall of the lower housing section 1.21 supports an insulating bushing 139, arranged in gastight relation therewith, through which. conductors are adapted to extend in order to supply the electric motor 137 with an operating current.

Considering now Vthe general operation of the elec.- trolytic cell 10, when the operating circuit Vfor the electric 'motor 137 is completed, operation thereof is initiated, whereby the 'operating shaft 52 is rotated, causing the bevel gear 51 to drive the bevel gear 47 in order vto rotate the shaft 41. As the shaft 41 is rotated the cathode members 46 are rotated, whereby repeatedly the lower segment of each of the Kcathode .members or disks 46 iS removed from the mercury pool 62 and immersed in the body of electrolyte in the associated one of the cathode compartments 31, and the upper segment .ther'eof is removed from the body of electrolyte .65 in the associated one of the cathode compartments 31 and immersed .inthe mercury pool -62. The electric motor137 is operated at a suitable speed in View of `the gear ref duction .ratio between the bevel gears 51 and 47 `so that the shaftx41 and consequently the disk 46 rotate at .the required speed, as explained more fully hereinafter. Also, the .operating circuit for the electrolytic .cell 10 is completed,the anode terminal 36 and thecathode plate 63 being respectively connected .to the positive and ,negative terminals of the source of direct current supply, whereby the body of electrolyte 65 floating on-the pool of mercury 62 is-electrolyzed. More particularly, a iirst solution to be treated in the electrolytic cell 10V is conf ducted through the .anode compartments 30 via the first conduitsystem mentioned;,and a second solution to betreated in .the electrolytic cell 10 is conducted through the cathode compartments 31 via the second conduit system mentioned; the two solutions forming an electrolyte system comprising the body of electrolyteS, as explained more ,fully hereinafter. Also, gas v under pressure is conducted intothe anode compartments 30 via the third conduit system mentioned fora purpose more fully Aexplained hereinafter. Finally, mercury is conducted ythrough .the lower casing section 11 4via the fourth conduit system mentioned. The mercury forms a partof the pool. of mercury .62, for a. purpose more fully explained hereinafter.

Considering now the construction and ,arrangement of the component elements of the electrolytic cell 10 in greater detai'hit is noted that in the specific embodiment of theelectrolytic cell illustrated, each of the disks 46 hasa ,diameterapproximately l2 cm., and approximately 40% and 60% of its area are respectivelyvimmersed in the body of electrolyte 65 and in the mercury pool 62.. Thus, about cm2 of the area of each of thefdisks 46 is immersed in the body of electrolyte 65, whereby the totali area of the cathode immersed in the body of elec- .trolyte '65 is approximately 720 cm?. Employing an electrolyte constituting a hydrochloric acid solution, an electrolytic current within the range to 175 amperes has been obtained, v.whereby the electrolytic current was approximatelyl ampere per cm.2 of area of the cathode, which value is well within the usual operating limits, 0.1 to 0.3 Aampere per cm.2 at the cathode, for electrolytic celils.

of relatively large volume, conducted through the three y The electrolytic current mentioned wasobtained when several volts, e. tg., ,about four, directcurrent was groups of anode compartments 30, and three streams of the second solution treated, of relatively small Volume, conducted through the three igroups of cathode compartments 31, permitted operation without undue heating of either the electroltyic cell 10 or the two solutions. More particularly, each of the three streams of the first solution comprised a liow of approximately 50 cc. per min-v ute, while each of the three streams of the second solution comprised a ow of approximately cc. per minute, the temperature rise of the two solutions being of the order of 55 C. Specifically, 150 cc. of the first solution per minute and l5 cc. of the second solution per minute were conducted through the electrolytic cell l0, eX- periencing a temperature rise from l520 C. to 70- 75 C. When the two solutions were conducted through the electrolytic cell at the rate and under the operating conditions mentioned, there was no undue heating of the component parts of the electrolytic cell. It will be understood that these particular ow rates, as well as the ratios between them, are given merely for the purpose of better illustrating the invention, and that wide variations may be made therein without sacrificing any of the advantages of the invention. ln general, it is preferred to maintain such relative rates of ow of the respective electrolyte solutions as will give satisfactory transfer of uranium from the rst solution to the second, without at the same time causing undue heating of the cell. It is also preferred to maintain the flow conditions such that the respective electrolytes in the anodes and cathode compartments are at substantially the same level, in order to prevent mechanical transfer of electrolyte through the partitions.

Now considering the operation of the electrolytic cell 10, in conjunction with the detailed treatment of the two solutions in accordance with the present process, reference is again made to Fig. 9. The anode and cathode compartments 30 and 31 are initially filled with a body of electrolyte comprising about 3 N hydrochloric acid; then operation of the electrolytic cell 10 is initiated in the manner previously explained. More particularly, the flow of the rst solution to be treated through the anode compartments 30 via the first conduit system mentioned is adjusted to approximately 150 cc. per minute. More specifically, the first solution may be an oxalic acid solution, about l N to 3 N in hydrogen ion, and normally contains traces of uranium and fairly large amounts of nickel, iron, copper and chromium. Ordinarily, the rst solution, or oxalate solution, contains the materials mentioned in the ionic forms U++++, Ni++, Fe++, Cut-*-v and Cr+++, although some of the uranium and the iron might possibly be in the ionic forms UO2++ and Fe+++g and the general case will be considered, wherein the first solution is assumed to contain the following ions: U03++, U++++, Ni++, Fe+++, Fe++, Cu++ and C1+++ The flow of the second solution to be treated through the cathode compartments 3l via the second conduit system mentioned is adjusted to approximately. l5 cc. per minute, this second solution constituting ordinary hydrochloric acid, about 12 N. Also, the flow of the gas through the anode compartments 30 via the third conduit system mentioned is suitably adjusted, whereby the gas is burbled and thoroughly dispersed through the electrolyte contained in the anode compartments 30, this gas being introduced adjacent the lower corners of the anode compartments well below the surface of the electrolyte contained therein. This gas comprises a mixture of nitrogen and chlorine, nitrogen being employed as a carrier for the chlorine and the chlorine being employed as an oxidizing agent, for a purpose more ful-ly explained hereinafter. Further, the ow of mercury through the lower casing section 11 via the fourth conduit system mentioned is suitably adjusted, whereby pure mercury is introduced into the mercury pool 62 and contaminated mercury is withdrawn therefrom, as explained more fully` hereinafter.

Shortly after operation the initial body of electrolyte 65 in the anode and cathode compartments 30 and 31, and the mixture of nitrogen and*g chlorine is burbtled through the rst solution conducted through the anode compartments 30, whereby the oxalate' solution is decomposed in order to prevent possible pre' cipitation of minor amounts of uranous oxalate in the anode compartments. More particularly, the xalate solution is readily decomposed by virtue of tw iride`` pendent, although cumulative, chemical actions which take place in the anode compartments. In the rst plac,- the oxalate solution is decomposed into carbon dioxide by anodic oxidation, due to contact between the oxalate ions and the anode elements 38 in the anode compart ments 30, as indicated below:

In the second place, the oxalate solution is decomposed into carbon dioxide and hydrochloric acid by chlorine oxidation, due to contact between the oxalate solution and the chlorine burbled therethrough in the anode compartments 30, as indicated below:

H2C2O4-j-Cl2- 2CO2-l-2HC1 It is noted that the decomposition of the oxalate solution by `chlorine oxidation is enhanced by virtue of the increased temperature of the oxalate solution as a result of the treatment in the electrolytic cell 10. The carbon dioxide thus produced in the anode compartments 30 escapes therefrom, along with some `of the chlorine and virtually all of the nitrogen originally introduced into the oxalate solution therein.

Furthermore, the hydrochloric acid thus produced in the anode compartments 30 by chlorine oxidation, as well as thev hydrochloric acid conducted through the cathode compartments 31, is decomposed to `a considerable extent by the electrolytic current into hydrogen and chlorine. The hydrogen ion migrates toward the cathode members 46, where hydrogen is liberated to some extent, and then escapes from the cathode compartments 31; while the chloride ion lmigrates to the anode elements 38, where chlorine is liberated freely, and then escapes from the anode compartments 30. These gases (hydrogen, nitrogen, chlorine and carbon dioxide) escape from the anode and cathode compartments 30 and 31 in the electrolytic cell 10, accumulate within the interior of the surrounding housing 120, and are conducted therefrom by way of the conduit 134 carried by the upper housing section 122. Preferably, the gases mentioned are suitably pumped from the interior of the housing 120, although this is not entirely necessary in view of the fact that the amounts of nitrogen and chlorine are adequate: to build up a slight pressure within the housing 120.

Also, it is noted that while it is preferable that a mixture of nitrogen and chlorine be introduced into the anode compartments 30 via the third conduit system in order to obtain rapid decomposition of the oxalate solution, this step is not essential as the oxalate solution may be decomposed-quite satisfactorily entirely by anodic oxidation. Of course, it will be understood that when the oxalate solution is decomposed entirely by anodic oxidation, the rate of decomposition is correspondingly decreased. Furthermore, aside from the fact that the introduction of the mixture of nitrogen and chlorine into the anode compartments 30 is productive of decomposition of the oxalate solution by chlorine oxidation, it

has been found to be desirable also from the 'standpoint that the burbling ofthe gas through the iirst solution conducted through the anode compartments 30 produces a stirring or agitating effect, resulting in an increased contact between the oxalate solution and the anode eleV ments 38 in the anode compartments 30 and the consequent increased rate of decomposition of the oxalate solution due to anodic oxidation, as previously explained.

of the electrolytic cell is ini# tiated, the iirst and second solutions respectively displace' Further, itis. pointed out that the above-mentioned stirring or agitation of the oxalate .solution in theanode compartments 30 may be brought about entirely by the introduction of only nitrogen via the third conduit system. Also, instead of introducing a mixture of. nitrogen and chlorine via the third conduit system, chlorine alone may be introduced into the anode compartments 30 in order to obtain the decomposition of the oxalate solution byV chlorine oxidation in the manner explained. Finally, in-this connection, it appears that the chlorine produced as a result of the decomposition o the second solution conducted through the cathode compartments 31, which migrates to the anode elements 38 in the anode compartments 30, also accounts for some of the decomposition by chlorine oxidation of the oxalate solution in the anode compartments, regardless of whether gas is introduced via the third conduit system into the anode compartments in the manner explained.

Also, as the rst solution is conducted through the anode compartments 3,0 of the electrolytic cell, it is subjected to electrolysis as previously explained, whereby the contained ions are diffused by the electrolytic current through the partition elements 28 into the second solution conducted through the cathode compartments 31. The flow of the first solution through the anode compartments 30 of the electrolytic cell 10 is appropriately correlated with respect to the electrolytic current therethrough, so that substantially all of the uranium and other metal ions are transferred by electrolytic diffusion from the first solution to the second solution, the first solution leaving the electrolytic cell containing only minor traces of uranium, nickel, iron, copper and chromium in the original ionic forms: UO2++, U++++, Ni++, Fe+++, Fe++, Cu++ and Cr+++. In view of the fact that substantially all of the uranium and other metal ions are transferred from the first solution to the second solution, a considerable concentration of the uranium in solution is effected, as the rate of fiow of the second solution is only approximately one-tenth of that of the lirst solution, as previously explained.

Furthermore, substantially all of the metal ions except uranium transferred to the second solution are reduced by the electrolytic current to the metallic state; while the uranium ions transferred to the second solution are reduced by the electrolytic current to the ionic form, U++++, in the event they are not already in this form, substantially none of the uranium ions being reduced to the metallic state, U0, due to the fact that uranium inherently possesses a high over-voltage. More particularly, the Fe+++ ion is first reduced to the Fe++ ion and then to the metal state Feo, while the Ni++, Crt++ and CutL ions are respectively reduced to the metal states Ni, Cron and Cu, which metal impurities in the second solution in the cathode compartments 31 are carried by the rotating disks 46 into the mercury pool 62. The metal impurities carried into the mercury pool 62 by the rotating disks 46 are either trapped therein or amalgamated therewith, whereby the second solution conducted throughv the cathode compartments 31 is kept substantially free of metal impurities liberated therein incident to the electrolysis. Specifically, the copper, chromium and nickel impurities readily amalgamate with the mercury in the mercury pool 62, whereas the iron impurity is trapped therein. In view of the fact that pure mercury is continuously conducted through the lower casing section 11 of the electrolytic cell 19, the metal impurities introduced into the mercury pool 62 are conducted therefrom along with the mercury.

Of` course it will be understood that the mercury conducted from the lower casing section 11 of the electrolytic cell 10 is subsequently purifedand again conductedthereto,y in order to prevent undue contamination of the mercury inthe mercury pool 62 and to effect the transfer of the metal impurities mentioned therefrom. Accordingly,

the second solution conducted from the electrolytic cell copper impurities.

10 comprises a hydrochloric acid solution containing subs stantially all of the uranium, inthe ionic form U.++++ and virtually none of the nickel, iron, chromium and. Thus, the treatment of the two soluf tions in the electrolytic cell is effective to transfer substantially all of the uranium contained in the relatively large volumeof the first solution to the relatively smallvolume of the second solution, and to remove virtually all of the metal impurities from the first solution withoutv introducing substantially any of these metal impurities into the second solution, the metal impurities being re-j moved from the first solution by electrolysis and intro-Y duced into the mercury which is circulated through the. lower casing section of the electrolytic cell. y

The first solution, after it is conducted from the electro-x lytic cell, may be discarded or subjected to further salvage'Y treatment in order to recover any minor traces of the. contained uranium; the second solution, after it is con-- ducted from the electrolytic cell, is then subjected to further salvage treatment in order to recover the contained uranium; while the impurities recovered from thevv mercury circulated through the lower casing section of the electrolytic cell may be salvaged in order to recover anyminor traces of uranium that may be trapped therein.

It will be understood that although the present invention is particularly useful for the separation and concert tration of uranium from impure uranium oxalate` solu-` tion, it also contemplated electrolytic processes wherein,

y other solutions, and/or other operational conditions such,-

as rates of oW, current densities, etc., are employed. Solutions of metal salts other than uranium salts may be. passed in non-mixing ion-transfer relation with other acidic electrolytes to separate and concentrate the metals; Substantially any compound that is decomposable by chlorine oxidation may be decomposed or oxidized by electrolysis in a system comprising a solution containing. chloride ion in ion transfer relation with a solution of,

the compound. Other known oxidizing gases than chlo.- Y

rine may be burbled through the solution to assist in oxidation. Thus, it will be clear that the process of the present invention is not restricted to the illustrative details given.

While there has been described what is at present considered to be the preferred embodiment of the inventiom it will be understood that various modifications may. be made therein and it is intended to cover in the appended. claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. An electrolytic cell comprising a casing having ay removable upper section provided with an apertured floor detachably secured to a lower casing section, a pool ofy mercury disposed within said casing, porous partitions: defining a plurality of alternately disposed, separate anode and cathode compartments within said casing, a plurality of elements constituting an anode and respectively dis.- posed in said anode compartments, a plurality of rotatably-mounted members constituting a cathode, said cathode being disposed with its greater surface beneathsaid floor and with its lesser surface extending through the Hoor into the upper casing section, portions of saidmem bers being immersed in said mercury pool and other por--Y tions of said members being respectively disposed in said.

cathode compartments, means for rotatngsaid members, whereby different portions of each of saidmembers are successively immersed in said mercury pool and moved into the corresponding one-of said cathode contpartments, said anode and cathode compartments being adapted to contain an electrolyte in contact with said elements and said members and electrically communicating through said porous partition structure, first Iterminal structure commonly connecting together said elements, second ter-V minal structure commonly connecting together said members, and conduit means for conducting gas intoeac'hcf said anode compartments below the surface of rsaid`ele'ctrolyte therein, whereby said gas is dispersed through said electrolyte in said anode compartments.

2. An electrolytic cell having Va casing comprising a re. movable upper section provided with an -apertured tloor member detachably secured to a lower casing section, a plurality of alternately disposed anode and cathode compartments separately contained within said casing, porous partition members sep-arating said compartments, each compartment being separated from each of its adjoining compartments by porous partitions common -to both comf partments, an anode, a cathode, said cathode being disposed wtih its greater surface beneath the oor member and with its lesser surface extending through said oor member into said upper casing section, said anode and cathode compartments being adapted to contain an electrolyte having a metallic ion content, conduit means connected to said anode compartments for continuously circulating a rst portion of the electrolyte containing metallic ions to be separated therefrom, conduit means connected to said cathode compartments for continuously circulating a second portion of the electrolyte for transporting from the cell at least a part of the metallic ions separated from said iirst portion of the electrolyte, and a source of electricity connected to said anode and cathode whereby metallic ions are transferred from the electrolyte in an anode compartment through partition members to the electrolyte in each of the adjoining cathode compartments.

3. An electrolytic cell of the character described in claim 2, in which said anode compartments are arranged in a plurality of groups and in which the conduit means connects said groups in parallel whereby said rst portion of electrolyte is conducted in parallel through said groups of anode compartments.

4. An electrolytic cell of the character described in claim 2, in which said anode compartments are arranged in a plurality of groups with the compartments within each group connected in series and in which the conduit means connects said groups in parallel whereby the iirst portion of electrolyte is conducted in parallel through said groups.

5. An electrolytic cell having a casing comprising a removable upper section provided with an apertured door member detachably secured to a lower casing section, a plurality of alternately disposed anode and cathode compartments separately contained within said casing, porous partition members separating vsaid compartments, each compartment being separated from each of its adjoining compartments by porous partitions common to both compartments, an anode, a cathode, said cathode being disposed with its greater surface beneath the iloor member and with its lesser surface extending through said oor member into said upper casing section, said anode and cathode compartments being adapted to contain an electrolyte having a metallic ion content, conduit means connected to said anode compartments for continuously circulating a rst portion of electrolyte containing metallic ions to be separated therefrom, conduit means connected to said cathode compartments for continuously circulating a second portion of electrolyte for transporting from the cell one part of the metallic ions separated from said rst portion of electrolyte, conduit means connected to said cell for continuously circulating a bath of electrically conductive material in said cathode compartments and for transporting from the cell another part of the metallic ions separated from said iirst portion of electrolyte, and a source of electricity connected to said anode and said cathode, whereby metallic ions are transferred from the rst portion of electrolyte in an anode compartment through partition members to the second portion of electrolyte in each of the adjoining cathode compartments.

6. An electrolytic cell having a casing comprising a removable upper section provided with an apertured oor member detachably secured to a lower casing section, a plurality of alternately disposed anode and cathode compartments separately contained within said casing, porous partition members separating said compartments, each compartment being separated from each of its adjoining compartments by porous partition members common to both compartments, an anode, a cathode, lsaid cathode being disposed with its greater surface beneath the oor 1 member and with its lesser surface extending through said oor member into said upper casing section, said anode and cathode compartments being adapted to contain an electrolyte, conduit means connected to said anode compartments for continuously circulating a rst portion of electrolyte containing metallic ions to be separated therefrom, conduit means connected to said cathode compartments for continuously circulating a second portion of electrolyte for transporting from the cell at least a part of the metallic ions separated from said first portion of electrolyte, conduit means connected to said anode compartments for introducing a gas into said compartments below the surface of the electrolyte therein, and a source of electricity connected to said anode and cathode whereby metallic ions are transferred from the electrolyte in an anode compartment through partition members to the electrolyte in each of the adjoining cathode compartments.

References Cited in the le of this patent UNITED STATES PATENTS 562,785 Schwahn June 23, 1896 699,415 Reed May 6, 1902 1,094,315 Earle et al April 21, 1914 1,315,543 Curme Sept. 9, 1919 1,840,105 Kean Jan. 5, 1932 2,193,323 Nitzschke et al. Mar. 12, 1940 2,234,967 Gilbert Mar. 18, 1941 2,259,046 Roberts Oct. 14, 1941 FOREIGN PATENTS 9,346 Great Britain July 16, 1892 

1. AN ELECTROLYTIC CELL COMPRISING A CASING HAVING A REMOVABLE UPER SECTION PROVIDED WITH AN APERTURED FLOOR DETACHABLY SECURED TO A LOWER CASING SECTION, A POOL OF MERCURY DISPOSED WITHIN SAID CASING, POROUS PARTITIONS DEFINING A PLURALITY OF ALTERNATELY DISPOSED, SEPARATE ANODE AND CATHODE COMPARTMENTS WITHIN SAID CASING, A PLURALITY OF ELEMENTS CONSTITUTING AN ANODE AND RESPECTIVELY DISPOSED IN SAID ANODE COMPARTMENTS, A PLURALITY OF ROTATABLY-MOUNTED MEMBERS CONSTITUTING A CATHODE, SAID CATHODE BEING DISPOSED WITH ITS GREATER SURFACE BENEATH SAID FLOOR AND WITH ITS LESSER SURFACE EXTENDING THROUGH THE FLOOR INTO THE UPPER CASING SECTION, PORTIONS OF SAID MEMBERS BEING IMMERSED IN SAID MERCURY POOL AND OTHER PORTIONS OF SAID MEMBERS BEING RESPECTIVELY DISPOSED IN SAID CATHODE COMPARTMENTS, MEANS FOR ROTATING SAID MEMBERS, WHEREBY DIFFERENT PORTIONS OF EACH OF SAID MEMBERS ARE SUCCESSIVELY IMMERSED IN SAID MERCURY POOL AND MOVED INTO THE CORRESPONDING ONE OF SAID CATHODE COMPARTMENTS SAID ANODE AND CATHODE COMPARTMENTS BEING ADAPTED TO CONTAIN AN ELECTROLYTE IN CONTACT WITH SAID ELEMENTS AND SAID MEMBERS AND ELECTRICALLY COMMUNICATING THROUGH SAID POROUS PARTITION STRUCTURE, FIRST TERMINAL STRUCTURE COMMONLY CONNECTING TOGETHER SAID ELEMENTS, SECOND TERMINAL STRUCTURE COMMONLY CONNECTING TOGETHER SAID MEMBERS, AND CONDUIT MEANS FOR CONDUCTING GAS INTO EACH OF SAID ANODE COMPARTMENTS BELOW THE SURFACE OF SAID ELECTROLYTE THEREIN, WHEREBY SAID GAS IS DISPERSED THROUGH SAID ELECTROLYTE IN SAID ANODE COMPARTMENTS. 